🚀 go-pugleaf

In article <9509080952.AA15973@jodium.cs.few.eur.nl>, Rogier Goossens <goossens@cs.few.eur.nl> writes:
|> 
|> I have another, related question:
|> 
|> For a 'pointer' type to be complete, it seems to me it needs an 'operator ->*'
|> as well.
|> 
|> How would such an operator be declared for a pointer<C> class ?
|> 
|> One possibility is:
|> 
|>     template<class C>
|>     class pointer {
|> 	public:
|> 	template<class TMC> 	// TMC : type of member of class C
|> 	TMC &pointer<C>::operator ->*(TMC *cmp);    // cmp: C member pointer
|> 	}
[..]
|> The semantics would then have to be something like:
|> 
|>     pointer<myclass> p;
|>     ...
|>     p->*memberptr;	    <-->  p->(p.operator->*(memberptr));
|>     p->*methodptr(...);	    <-->  p->(p.operator->*(methodptr))(...);
[..]
|> To resume:
|> - Is such a declaration for operator->* possible at all, and if so, is
|>   the declaration above correct.

AFAIK it is possible. ->* is overloadable (13.5[over.oper],3).

5.5[expr.mprt.oper],3:
  ... second operand, which shall be of type "ptr to mem of T" to it's
                                              ^^^^^^^^^^^^^^^
  first operand, which shall be of type ptr to T ...
  The result is ... of the type specified by the second argument.

Instead of template parameter 'TMC: type of member of class C',
I'd suggest 'TPMC: type of ptr to member of class C'.
Then you can forget about TMC& and TMC*.

|> - If it is possible, are 'my' semantics of operator->* correct.

Using operator-> and operator->* to describe semantics of userdefined
operator->* confuses me. I prefere an implementation that is based
on the non-overloadable operator.*:

template<class C, class TPMC>           // TPMC: type of ptr to member of C
TPMC auto_ptr<C>::operator->*(TPMC pmc) //  pmc: a ptr to member of C
{
	return (*get()).*pmc;
}

[ Is this the correct syntax for template members of a template class? ]

For orthogonality with (the not so old feature of) memberpointers
(that can be used on objects by .* and on built-in pointers by ->*)
I would appreciate if operator->* would be a standard part of auto_ptr.

Ulf Schuenemann

--------------------------------------------------------------------
  ,_.   Ulf Schünemann
 #,  \  Fakultät für Informatik, Technische Universität München, Germany.
  |   > email: schuenem@informatik.tu-muenchen.de
  v==-<  WWW:   http://hphalle2.informatik.tu-muenchen.de/~schuenem/
        ...there is only one way to "skin a C+@"...:)  -- Jim Fleming

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